Electric ignition generator



May 24, 1938. L. P. KONGSTED ELECTRIC IGNITION GENERATOR 2 Sheets-Sheet 1 Filed Feb. 13, 1937 IN VENTOR. Zzuivz'gl? Kama-Zed ATTORNEY.

May 24, 1938. 1.. P. KONGSTED ELECTRIC IGNITION GENERATOR Filed Feb. 13, 1957 2 Sheets-Sheet 2 IIIIIHIHHHII [lllllllllllll X7 INVENTOR.

ladl q'qfljfalyskd In Q0 ATTORNEY.

Patented May 24,193a 2,118,313

UNITED STATES PATENT OFFICE ELECTRIC IGNITION GENERATOR Ludvig P. Kongsted, Longmeadow, Mass, assignor to United American Bosch Corporation, Springfield, Mass, a corporation of New York Application February 13, 1937, Serial No. 125,540

9 Claims. (Cl. I'll-20! This invention relates to electric generators for lowing detailed description taken in conjunction ignition circuits, and particularly to one of simwith the accompanying drawings in which:

ple and inexpensive construction for high speed Fig. l is a diagrammatic view showing the aroperation of multicylinder internal combustion l'angement of mechanism and circuits of a magengines, neto constructed in accordance with this inven- 5- Magnetos for use with high speed multicylintion and applicable to an eight-cylinder fourder engines have usually employed permanent cycle internal combustion engine; Fig. 2 is a view magnets, but on account of the time delay in the similar to Fig. 1 of a modification applicable to magnetic saturation of the generating winding a six-cylinder four-cycle engine; Fig. 3 is a furthereof, the voltage and energy delivered is inther modification applicable to a four-cylinder 10 sumcient for reliable ignition at the extremely four-cycle engine; Fig. 4 is a wiring diagram; high engine speeds now prevalent or desired, par- Fig. 5 shows a longitudinal section through a ticularly with high compression engines, with the magneto of the timer-distributor type having the 'result that the speed or the compression ratio, magnetic circuit of Fig. 1; Fig. 6 is an end view or both, were kept below the value desired. Ex-' of the same with parts removed to show the in- 15 ternally excited electromagnets have been used ternal construction; and Fig. 7 is an alternative to replace or reenforce the permanent magnets, wiring diagram of the field circuit. but in these magnetos also, the delay in magnetic Referring to Fig. 1, reference numerals l and 2 saturation has limited the output of the magneto indicate externally excited field coils for magbelow present requirements due in part to the netizing the cores 3 and 4 respectively of the mag- 20 ineffectiveness of the external excitation to bring neto. These cores are of laminated sheet steel about a sufllciently rapid rate of flux reversal of of high permeability and otherwise well known sufficiently large amplitude through the generatcharacteristics and are provided with upwardly ing winding. 7 extending shanks 5 and 6 which are magnetically In ac ordance withniy invention the foregoing connected to the ends of the core 1 of the gener- 25 disadvantages are overcome and satisfactory ating coil 8 comprising primary and secondary sparking obtained at higher continuous speeds windings 8 and 8". The core 3 also has pole and higher compression ratio than heretofore pieces 9 and i0 extending inwardly from its upper Po y arranging the magnetic c cu t of and lower ends and similar pole pieces i I and i2 the magneto in such manner that certain DOrare provided for core 4. The unmagnetized rotor 30 tions thereof are selected to bring about the conll of similar laminations has four radial arms duction of magnetic flux through the core of the H which coact with the pole pieces 9, III, I l, and eneratin w in firs n ne di i n and I: to alter the magnetic circuit therethrough in then in the other, with a reversal thereof that is a, manner which will be hereinafter more fully extremely r p w n the limits f s z described. It will be observed at this point that 35 tion. In such a magnetic circuit, the time delay all magnetic circuits are completely laminated inof magnetization of the core of the generating cluding the flux generating elements 3 and 4 winding is" reduced by externally excited electrowhich differ in this important respect from the magnets, preferably by means of a plurality of ma ets us P a e t magnet magnetos. field coils in series, by arrangement or in eifect, The 00115 I and 2 are a ly connected in 40 to boost or reinforce the magnetizing eifect of 561195 with each other F fl tt y l5 each other and thereby bring about the reversal through the ignition switch ii. The direction of flux through the core of the generating of current flow through the coils is such that the mg or ignition con with grater rapidity and shanks 5 and 6, which are magnetically consharpness. In the preferred form of this magnected to opposite. ends of the t core are of 45 neto, advantage is taken of the fact that one or the Same magnet: polarity Indicated by N more of the alternative magnetizing paths may and S, the dotted letters indicating that the magbe periodically open circuited without weakening new: g i g i E qplece and the pole the strength thereof upon subsequently connect- 5:553 z i opened it r2 1 211%: ii l i'g i 3 ;232:5 core of the generating wind rotor than when closed later in the rotatio r n v Assuming switch It closed and rotor I: turn- The above and other ob ects and features of ju clockwise as indicated by th arrow, h

this invention will be more apparent to those t part are in th position shown in p g. 1 skilled in the art from a consideration of the folwith n of the rqtor arms I adjacent pole p 55 9 and the diametrically opposite arm adjacent pole piece I2, a magnetic circuit is provided from the north pole of core 4 by way of shank 6 and. coil core I to shank 5, and thence by way of pole piece 9 through said arms of the rotor to pole piece I2 forming the south pole of core 4. When the rotor is in the dotted line position, or 45 from the former position, the path through core 4 is open and the path through core 3 is closed. l'he magnetic circuit is now from the north pole of core 3 by way of shank 5 through core I and thence by way of shank 6 and pole piece II through diametrically opposite arms I4 of rotor I3 to the pole piece I0 forming the south pole of core 3. This reversal of the magnetic flux in core I occurs between the full and dotted line positions of rotor I3 at the instant each pair of diametrically opposed arms I4 passes into or out of cooperation with the pole pieces 9, I0, II and I2. At'each of these instants, the reversal of flux in the core I is extremely rapid from, its full value in one direction to its full value in the other direction. This reversal of flux at the extreme'high time rate of change induces an unusually high voltage in the secondary winding 8" of the generating coil at all speeds from a low speed in starting or at idling to a very high speed in operation, particularly since the interrupter H in the primary winding 8' of the generating coil is opened at the same instant. This rapid reversal is due in part to the completely laminated magnetic members in which the flux is generated and by which, it is conducted. It is, however, more due to the arrangement by which the current in the field coil 2 of the core 4 then becoming active is boosted by the current generated in the-other field coil I during reversal of the flux in the coil 1. This boosting effect results from the fact that the turns of the field coil I are then cut by the flux disappearing in its core 3 to thereby generate an electromotive force in the same direction as the electromotive force of the battery. The additional current resulting from this added electromotive force flows to the field coil 2 to increase at the instant the rapidity with which the flux is built up in its core 4. Without such a boosting effect of one field coil on the other, at each period of flux reversal, the flux established by the core then becoming active would increase at a reduced rate because the counter-electromotive force generated in it by the establishment of the fiux through its core opposes that of the battery.

As a result of the fact that at each period of flux reversal the magnetic circuit through one of the cores, 3 or 4 is'open, the flux thenpassing through rotor I8 and also through the air gaps is that flux produced by only one field coil. This factor, resulting in lower flux densities in the air .gap and-pole pieces than would otherwise be the case, contributes to a still further increase in the rapidity of the flux reversal at each period of ignition. It will be noted that in a position intermediate those shown in full and dotted lines' in Fig. 1 or as shown in Fig. 6, the magnetic circuits through both coil cores 3 and 4 are inomentarily closed through adjacent rotor arms I4.

This helps the flux through coil I build up and.

Figs. 2 and 3 will now be obvious to those skilled in the art. The same reference numerals have been applied to similar parts in each of the embodiments. Further modifications necessary to adapt the invention to provide magnetos serving any other number of cylinders of either two or four cycle engines will be apparent to those skilled in the art from a consideration of the forms shown.

Referring to Figs. 5 and 6, which illustrate a physical embodiment of my invention, the rotor I3 is fixed to.the timer or cam shaft I8 which is rotatable in housing I9 having an endplate 28 and an integral internal partition 2I which provide suitable bearings for the shaft. The field coils I and 2 are positioned on the sides of the housing in non-magnetic cup-shaped protective covers 22 which may be readily detached from the housing I9 by screws 23. The cores 3 and 4 are held in position by spring brackets 24 riveted in the cup-shaped members. The shanks 5 and 6 extend through an upwardly projecting portion of the housing I8 and support the outer ends 01 core I. 'I'he'generating coil 8 is separately housed in a cylindrical insulating member 25 which projects into the upwardly extending portion of housing I9. Caps 28 hold the core I on shanks 5 and 6. A centrifugal governor 21 controls the timing of the interrupter cam 28 in the well known way. A plate 28, which is preferably adjustable manually or otherwise, carries the interrupter II, capable of operation at sufficiently high speed, adjacent the cam 28. A distributor rotor 38, for a conventional distributor cap II, is mounted on the outer end of cam 28.

From the foregoing description taken in conjunction with the accompanying drawings, it will be seen thatl have provided a magneto structure in which a pair of externally excited magnets are alternately connected in magnetic circuit through the core of a generating coil in such manner that the magnetic flux through the generating coil is rapidly reversed, and that at the instant of reversal one of the externally excited field coils boosts the other field coil to thereby augment the rate of this fiux reversal.

I have described the principles of operation of the invention in connection with the preferred form of the apparatus. It will be understood that the apparatus shown is merely illustrative and that changes may be made as desired by .those skilled in the art within the scope of the appended claims. For instance, the magneto may have permanent magnets to replace or supplement the electromagnets. Also, the generating coil 8 may comprise'a primary winding only for low tension ignition or for supplying interrupter currents to an outside high tension ignition coil in the well known way. Also this magneto may be arranged for ignition of two-cycle or other engines, and for ignition of engines of various types requiring sparks at irregular intervals' Also the magneto may be driven at otherthan cam-shaft speed, in which case distributor gearing may be necessary. Also the externally excited field coils may be connected in electrical parallel with each other and the beneficial effect of the series arrangement obtained by the use of a high reactance or transformer with center tap.

connected in the circuit between the battery and held coils, as. for instance by coupling .coil 42 shown in Fig. 7., In this arrangement the current enters the center tap of the transformer 42 and at standstill conditions the current divides equally between the two field circuits land 2, and

the resultant magnetic flux .in the transformer core is practically zero since the two fields oppose each other. During rotation of the magneto the fiux pulsations in l and 2 which occur alternately will induce voltage and current pulsations which will tend to oppose the change in flux. Thus assume for the moment that the flux through the core of I is collapsing. A voltage and current is immediately generated which tends to maintain the flux through I. This increase in average field current through the branch circuit I will induce a voltage and current in the opposite direction in' the other half of the transformer winding which will be in the same direction as the normal field current in 2, thus strengthening or reinforcing this circuit at the proper moment when an increase in fiux must take place.

Having thus described the invention, what is claimed is: I

1. In an externally excited ignition generator, a generating winding, externally excited field coils, a rotor for conducting magnetic flux from the field coils in reverse directions through the generating winding, means for closing the magnetic circuit from one field coil through the generating winding and opening the magnetic circuit from another field coil, and electrical connections for the field coils whereby a decrease in magnetic flux in one field coil induces a current which augments the current in the other field coil.

2. In an externally excited ignition generator, a generating winding, two externally excited field coils electrically connected in series,a rotor for conducting magnetic flux from the field coils in reverse directions through the generating winding, means for closing the magnetic circuit from one field coil through the generating winding and opening the magnetic circuit from another field coil, and electrical connections for the field coils whereby a decrease in magnetic flux in one field induces a current which augments the current in the other field coil.

3. In an externally excited ignition generator, a generating winding, two externally excited field coils electrically connected in parallel, a rotor for conducting magnetic flux from the field coils in reverse directions through the generating winding, means 'for closing the magnetic circuit from one field coil through the generating winding and opening the magnetic circuit from another field coil, and'a mutual inductance in the electrical circuit of the field coils whereby a decrease in magnetic fiux in one field induces a current which augments the current in the other field coil.

4. In an externally excited generator, at generating winding, two externally excited field coils, means for alternately conducting magnetic flux from one exciting coil in one direction through the generating winding and for conducting magnetic fiux from the other field coil in the reverse direction through the generating winding, and electrical connections for said field coils so arranged that the decline of the magnetic flux through one field coil boosts the current through the other field coil.

5. In an externally excited generator, 9. generating winding, two externally excited field coils, means for alternately conducting magnetic fiux from one exciting coil in one direction through the generating winding and for conducting magnetic flux from the other field coil in the reverse direction through the generating winding, and series electrical connections for said co s whereby the decline of magnetic flux through one field coil boosts the current flowing through the other field coil.

6. In an externally excited generator, a generating winding, two externally excited field coils, stator magnetic members for said field coils, means for alternately conducting magnetic flux from one exciting coil in one direction through said generating winding and for conducting magnetic fiux from the other field coil in the reverse direction through the generating winding,

means for short circuiting the magnetic circuits of both coils simultaneously between the periods of fiux reversal, and electrical connections for said field coils so arranged that the decline of the magnetic flux through one field coil boosts the current flowing through the fieldcoil having its magnetic circuit closed through the generating winding.

7. In an externally excited generator, a generating winding with a magnetic core, two externally excited field coils, cores for the field coils having similar poles magnetically connected to respective ends of the core of the generating winding, a rotor adapted to magnetically connect a pole of the core of one field coil to a diametrically opposite pole of the core of the other field coil, whereby the magnetic flux through one field coil is'first conducted in one direction through the generating winding and then the magnetic flux from the other field coil is conducted in reverse direction through the generating winding, and electrical connections between said field coils so arranged that the decline in the magnetic flux through one field coll boosts the current flowing through the other field coil during the period that the magnetic circuit of the second field coil is closed through said generating winding.

8. In a magneto, an unmagnetized rotor, a generating winding having a core, polepieces attached to each end of said core and having pole Lfaces positioned above the horizontal median of said rotor, externally excited field coils having cores magnetically connected to each polepiece in like polarity relation, and other pole faces positioned below said horizontal median and having a magnetic polarity opposite that of said first mentioned pole faces, means including said rotor for alternately closing the magnetic circuit from one field coil through the generating winding and opening a magnetic circuit from the other field coil, and electrical connections between said coils so arranged that the current generated by the decline of magnetic flux through one field coil boosts the current flowing through the other field coil.

9. In an externally excited generator, 9. generating winding, externally excited field windings, electrical connections between said field windings, means including a rotor for closing the magnetic circuit from a part of the field winding through the generating winding and simultaneously opening the magnetic circuit from another part of the field winding and subsequently clomng the magnetic circuit which was previously open and opening the magnetic circuit which was previously closed, said' electrical connections between said field windings being so arranged that a decrease in magnetic flux in the open magnetic circuit of one part of the field winding induces a current which augments the current in that part of the field winding having its magnetic circuit closed through the generating winding.

LUDVIG P. KONGBTED. 

